Turbo Charging

RW,

That was a terrific "potted" history of Rotax 9 development- my thanks.

The section on the 914 stood out for me.

"In 1993, the Rotax 912 engine was modified and equipped with a turbocharger for an altitude flight test. The airplane (HK36 Super Dimona model) reached an altitude of 33,000 feet (approx. 11,000 m). The concept was successful. The company started the development of the turbocharged Rotax 914 engine with 115 hp, and serial production began in 1996."

It would seem that the desire to achieve high altitude flight, may have been the reason for selecting a TCU, rather than a mechanical wastegate.

I am assuming that a mechanical wastegate would not have the "range " to respond to sea level - 33,000ft changes in atmospheric pressure.

😈